Methods and apparatuses for mechanical and chemical-mechanical planarization of microelectronic-device substrate assemblies of planarizing pads

ABSTRACT

Apparatuses and methods for planarizing a microelectronic-device substrate assembly on a planarizing pad. In one aspect of the invention, material is removed from the substrate assembly by pressing the substrate assembly against a planarizing surface of a planarizing pad and moving the substrate assembly across the planarizing surface through a planarizing zone. The method also includes replacing at least a portion of a used volume of planarizing solution on the planarizing surface with fresh planarizing solution during the planarization cycle of a single substrate assembly. The used planarizing solution can be replaced with fresh planarizing solution by actively removing the used planarizing solution from the pad with a removing unit and depositing fresh planarizing solution onto the pad in the planarizing zone. The used planarizing solution, for example, can be removed either while the substrate assembly is moved through the planarizing zone, or between planarizing stages of a multi-stage planarizing process. In another aspect of the invention, a planarizing machine for planarizing microelectronic-device substrate assemblies includes removing unit at the accumulation zone to actively remove used planarizing solution from the accumulation zone on the stationary planarizing pad.

TECHNICAL FIELD

[0001] The present invention relates to methods and apparatuses forplanarizing microelectronic-device substrate assemblies, and to methodsfor mechanical and chemical-mechanical planarization of such substrateassemblies on planarizing pads.

BACKGROUND OF THE INVENTION

[0002] Mechanical and chemical-mechanical planarizing processes (“CMP”)are used in the manufacturing of electronic devices for forming a flatsurface on semiconductor wafers, field emission displays and many othermicroelectronic-device substrate assemblies. CMP processes generallyremove material from a substrate assembly to create a highly planarsurface at a precise elevation in the layers of material on thesubstrate assembly.

[0003]FIG. 1 schematically illustrates an existing web-formatplanarizing machine 10 for planarizing a substrate 12. The planarizingmachine 10 has a support table 14 with a top-panel 16 at a workstationwhere an operative portion (A) of a planarizing pad 40 is positioned.The top-panel 16 is generally a rigid plate to provide a flat, solidsurface to which a particular section of the planarizing pad 40 may besecured during planarization.

[0004] The planarizing machine 10 also has a plurality of rollers toguide, position and hold the planarizing pad 40 over the top-panel 16.The rollers include a supply roller 20, first and second idler rollers21 a and 21 b, first and second guide rollers 22 a and 22 b, and atake-up roller 23. The supply roller 20 carries an unused orpre-operative portion of the planarizing pad 40, and the take-up roller23 carries a used or post-operative portion of the planarizing pad 40.Additionally, the first idler roller 21 a and the first guide roller 22a stretch the planarizing pad 40 over the top-panel 16 to hold theplanarizing pad 40 stationary during operation. A motor (not shown)drives at least one of the supply roller 20 and the take-up roller 23 tosequentially advance the planarizing pad 40 across the top-panel 16. Assuch, clean pre-operative sections of the planarizing pad 40 may bequickly substituted for used sections to provide a consistent surfacefor planarizing and/or cleaning the substrate 12.

[0005] The web-format planarizing machine 10 also has a carrier assembly30 that controls and protects the substrate 12 during planarization. Thecarrier assembly 30 generally has a substrate holder 32 to pick up, holdand release the substrate 12 at appropriate stages of the planarizingcycle. A plurality of nozzles 33 attached to the substrate holder 32dispense a planarizing solution 44 onto a planarizing surface 42 of theplanarizing pad 40. The carrier assembly 30 also generally has a supportgantry 34 carrying a drive assembly 35 that translates along the gantry34. The drive assembly 35 generally has an actuator 36, a drive shaft 37coupled to the actuator 36, and an arm 38 projecting from the driveshaft 37. The arm 38 carries the substrate holder 32 via another shaft39 such that the drive assembly 35 orbits the substrate holder 32 aboutan axis B-B offset from a center point C-C the substrate 12.

[0006] The planarizing pad 40 and the. planarizing solution 44 define aplanarizing medium that mechanically and/or chemically-mechanicallyremoves material from the surface of the substrate 12. The planarizingpad 40 used in the web-format planarizing machine 10 is typically afixed-abrasive planarizing pad in which abrasive particles are fixedlybonded to a suspension material. In fixed-abrasive applications, theplanarizing solution is a “clean solution” without abrasive particlesbecause the abrasive particles are fixedly distributed across theplanarizing surface 42 of the planarizing pad 40. In other applications,the planarizing pad 40 may be a non-abrasive pad without abrasiveparticles composed of a polymeric material (e.g., polyurethane) or othersuitable materials. The planarizing solutions 44 used with thenon-abrasive planarizing pads are typically CMP slurries with abrasiveparticles and chemicals to remove material from a substrate.

[0007] To planarize the substrate 12 with the planarizing machine 10,the carrier assembly 30 presses the substrate 12 against the planarizingsurface 42 of the planarizing pad 40 in the presence of the planarizingsolution 44. The drive assembly 35 then orbits the substrate holder 32about the offset axis B-B to translate the substrate 12 across theplanarizing surface 42. As a result, the abrasive particles and/or thechemicals in the planarizing medium remove material from the surface ofthe substrate 12.

[0008] CMP processes should consistently and accurately produce auniformly planar surface on the substrate assembly to enable precisefabrication of circuits and photo-patterns. During the fabrication oftransistors, contacts, interconnects and other features, many substrateassemblies develop large “step heights” that create a highly topographicsurface across the substrate assembly. Yet, as the density of integratedcircuits increases, it is necessary to have a planar substrate surfaceat several stages of processing the substrate assembly becausenon-uniform substrate surfaces significantly increase the difficulty offorming sub-micron features. For example, it is difficult to accuratelyfocus photo-patterns to within tolerances approaching 0.1 μm onnon-uniform substrate surfaces because sub-micron photolithographicequipment generally has a very limited depth of field. Thus, CMPprocesses are often used to transform a topographical substrate surfaceinto a highly uniform, planar substrate surface.

[0009] In the competitive semiconductor industry, it is also highlydesirable to have a high yield in CMP processes by quickly producing auniformly planar surface at a desired endpoint on a substrate assembly.For example, when a conductive layer on a substrate assembly isunder-planarized in the formation of contacts or interconnects, many ofthese components may not be electrically isolated from one anotherbecause undesirable portions of the conductive layer may remain on thesubstrate assembly over a dielectric layer. Additionally, when asubstrate assembly is over planarized, components below the desiredendpoint may be damaged or completely destroyed. Thus, to provide a highyield of operable microelectronic devices, CMP processing should quicklyremove material until the desired endpoint is reached.

[0010] The web-format machine 10 produces good results in applicationsthat use a stationary planarizing pad 40 and orbit the substrateassembly 12 about the offset axis B-B. One problem of CMP processingthat the planarizing machine 10 addresses is the center-to-edgeplanarizing profile produced by conventional planarizing machines thathave a rotating platen and a substrate holder that rotates about thecenter point of the substrate. In conventional rotating platen machines,the rotation of both the planarizing pad and the substrate holder causesthe relative velocity between the substrate assembly and the pad to beconsistently higher at the perimeter of the substrate assembly than thecenter. The polishing rate accordingly varies from the center of thesubstrate assembly to the perimeter causing a center-to-edge planarizingprofile. The web-format machine 10 reduces the center-to-edgeplanarizing profile by orbiting the substrate holder 32 about the offsetaxis B-B and holding the planarizing pad 40 stationary to reduce thedifference in relative velocity between the substrate assembly 12 andthe pad 40 across the surface of the substrate assembly 12.

[0011] The web-format planarizing machine 10 also produces highly planarsurfaces when substrate assemblies are planarized on a fixed-abrasiveplanarizing pad 40 and a “clean” planarizing solution 44, i.e., aplanarizing solution without abrasive particles. Because the abrasiveparticles are fixedly bonded to the pad 40, the particles cannotagglomerate in the planarizing solution or accumulate on the planarizingsurface in waste matter accumulations. The fixed distribution ofabrasive particles on the pad also provides a desired distribution ofabrasive particles under the substrate assembly that is not a functionof the distribution of the planarizing solution under the substrateassembly. Thus, the planarizing machine 10 is particularly useful inapplications that orbit a substrate across a stationary fixed-abrasivepad in the presence of a clean planarizing solution.

[0012] Although the web-format planarizing machine 10 is particularlyuseful for fixed-abrasive applications with clean planarizing solutions,it may also be desirable to use the web-format machine 10 withnon-abrasive planarizing pads and slurries having abrasive particles.One reason for using the planarizing machine 10 with non-abrasive padsand abrasive slurries is that fixed-abrasive planarizing pads and cleanplanarizing solutions may not be available for the structures andchemistries required for many CMP applications. For example,fixed-abrasive pads and clean solutions used to planarize a metal layerof aluminum, copper, tungsten, or titanium in the formation of highlyconductive interconnects are not widely available for the web-formatmachine 10. Thus, many CMP applications may require the use ofweb-format machines 10 with non-abrasive pads and abrasive slurries.

[0013] One drawback of CMP, and particularly the planarizing machine 10,is that it is difficult to planarize metal layers using non-abrasivepads and abrasive slurries. CMP of metal layers generally involvesoxidizing the surface of the metal layer with oxidants in the slurry,and removing the oxidized metal ions from the metal layer with theabrasive particles in the slurry. The metal ions removed from thesubstrate 12, however, may become reattached to the substrate 12 wherethey can create current leakage paths or other defects. In applicationswith high ionization rates or in which the slurry accumulates on thepolishing pad, the likelihood that metal ions will reattach to thesubstrate surface increases because the concentration of metal ions inthe slurry increases. Thus, planarizing metal layers using theweb-format planarizing machine 10 or machines having slow movingpolishing pads may cause significant defects that reduce the yield ofoperable microelectronic devices.

[0014] Another drawback of planarizing substrate assemblies usingnon-abrasive pads and abrasive slurries is that the abrasive particlesmay accumulate on the pad or agglomerate in the slurry. These problemsare particularly present when planarizing metal layers on the stationarypad of the web-format planarizing machine 10. The accumulations ofabrasive particles on the planarizing pad 40 typically alter theabrasiveness of the planarizing pad, and thus they also alter theconsistency of the polishing rate across the planarizing pad.Additionally, the agglomerations of the abrasive particles in the slurrymay alter the abrasiveness of the slurry. In extreme cases, theagglomerations of the abrasive particles in the slurry may scratch thesurface of the substrate 12. Therefore, the web-format planarizingmachine 10 may not produce sufficiently planar substrate assembliesand/or may produce defects in the substrate assemblies when planarizingmetal layers with non-abrasive planarizing pads and abrasive slurries.

SUMMARY OF THE INVENTION

[0015] The present invention is directed toward apparatuses and methodsfor planarizing a microelectronic-device substrate assembly on aplanarizing pad. In one aspect of the invention, material is removedfrom the substrate assembly by pressing the substrate assembly against aplanarizing surface of a planarizing pad and moving the substrateassembly across the planarizing surface through a planarizing zone. Themethod also includes replacing at least a portion of a used volume ofplanarizing solution on the planarizing surface with fresh planarizingsolution during the planarization cycle of a single substrate assembly.The used planarizing solution can be replaced with fresh planarizingsolution by actively removing the used planarizing solution from the padwith a removing unit and depositing fresh planarizing solution onto thepad in the planarizing zone. The used planarizing solution, for example,can be removed either while the substrate assembly is moved through theplanarizing zone, or between planarizing stages of a multi-stageplanarizing process.

[0016] In another aspect of the invention, a planarizing machine forplanarizing microelectronic-device substrate assemblies includes a tablewith a support panel, a planarizing pad attached to the support panel toremain stationary during a planarizing cycle, and a carrier assemblyhaving a substrate holder positionable over the planarizing pad. Theplanarizing pad has a planarizing surface facing away from the supportpanel, and the carrier assembly has a planarizing solution dispenser todispense a fresh planarizing solution onto the planarizing surface. Thecarrier assembly translates the substrate assembly over the planarizingzone of the planarizing surface during a planarizing cycle, and thesubstrate assembly pushes used planarizing solution deposited onto theplanarizing pad into one or more accumulation zones on the pad. Theplanarizing machine also includes a planarizing removing unit at theaccumulation zone to actively remove used planarizing solution from theaccumulation zone on the stationary planarizing pad.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a schematic side elevational view of a web-formatplanarizing machine in accordance with the prior art.

[0018]FIG. 2 is a schematic isometric view partially illustrating aweb-format planarizing machine with a planarizing solution removing unitin accordance with an embodiment of the invention.

[0019]FIG. 3 is a schematic cross-sectional view partially illustratinga microelectronic-device substrate assembly being planarized at onestage of a method in accordance with an embodiment of the invention.

[0020]FIG. 4 is a schematic isometric view partially illustrating aweb-format planarizing machine with another planarizing solutionremoving unit in accordance with another embodiment of the invention.

[0021]FIG. 5 is a schematic isometric view partially illustrating stillanother web-format planarizing machine with a continuous planarizingsolution removing unit in accordance with still another embodiment ofthe invention.

[0022]FIG. 6 is a schematic cross-sectional view of the web-formatplanarizing machine of FIG. 5.

[0023]FIG. 7 is a schematic isometric view partially illustrating yetanother web-format planarzing machine with another planarizing solutionremoving unit in accordance with another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0024] The present disclosure describes planarizing machines and methodsfor mechanical and/or chemical-mechanical planarizimg of substrateassemblies used in the fabrication of microelectronic devices. Manyspecific details of certain embodiments of the invention are set forthin the following description, and in FIGS. 2-7, to provide a thoroughunderstanding of the embodiments described herein. One skilled in theart, however, will understand that the present invention may haveadditional embodiments, or that the invention may be practiced withoutseveral of the details described in the following description.

[0025]FIG. 2 is a schematic isometric view partially illustrating aweb-format planarizing machine 110 for planarizing a substrate 12 inaccordance with one embodiment of the invention. The planarizing machine110 has a table 14 with a top-panel 16, a carrier assembly 30 forcarrying the substrate 12, and an operative portion of a web-formatplanarizing pad 40 on the top-panel 16. The planarizing pad 40 alsogenerally has pre-operative and post-operative portions wrapped aroundsupply and take-up rollers (not shown in FIG. 2). The carrier assembly30, the planarizing pad 40 and the supply and take-up rollers can besimilar to those described above with respect to the planarizing machine10 in FIG. 1. The planarizing pad 40 accordingly remains stationaryduring planarization, and a planarizing fluid 44 flows through aplurality of nozzles 33 onto the planarizing surface 42 of theplanarizing pad 40. Unlike the planarizing machine 10, however, theweb-format planarizing machine 110 also includes a removing unit 180 foractively removing used planarizing solution from the planarizing pad 40.

[0026] The embodiment of the removing unit 180 shown in FIG. 2 has anactuator 182 attached to the gantry 34 and a rotating brush 184 coupledto the actuator 182. The brush 184 is generally a non-abrasive brushwith a plurality of bristles 185. In a preferred embodiment, thebristles 185 are approximately 0.125-0.5 inch strands of polyvinylalcohol or other suitable materials that do not abrade or scratch theplanarizing pad 40. The bristles 185 are also preferably packed togetherin a high density. In alternative embodiments (not shown), the brush 184can be a fixed brush with bristles that project downward from an armcoupled to the actuator 182, or a wiper blade can be attached to thearm.

[0027] In operation, the carrier assembly 30 lifts the substrate 12 fromthe pad 40, and then the actuator 182 rotates the brush 184 (arrow R)and sweeps the brush 184 (arrow S) across the planarizing surface 42.The actuator 182 preferably sweeps the brush 184 across the pad 40 in adirection counter to the rotation R of the brush 184 at the planarizingsurface 42. As the actuator 182 sweeps the brush 184 across theplanarizing surface 42, the bristles 185 wipe used planarizing solutionon the planarizing surface 42 into a trough 186 (arrow W) to remove usedplanarizing solution from the pad 40. The trough 186 channels theplanarizing solution removed from the pad (arrow D) to a reservoir (notshown).

[0028] One method for operating the planarizing machine 110 is amulti-stage planarizing process in which a planarizing cycle of a singlesubstrate has a first stage to remove material from the substrate 12 toan intermediate level, a cleaning stage to remove used or residualplanarizing solution from the pad 40, and a second stage to removeadditional material from the substrate 12 with fresh planarizingsolution 44. At the first-stage of the planarizing process, the carrierassembly 30 presses the substrate 12 against planarizing surface 42 andmoves the substrate 12 through a planarizing zone 46 until the surfaceof the substrate 12 reaches an intermediate point prior to the finaldesired endpoint of the substrate 12. During the first-stage of theplanarizing process, an initial batch of planarizing solution 44 flowsthrough the nozzles 33 onto the pad 40, and the substrate 12 pushes atleast a portion of the initial batch of planarizing solution 44 out ofthe planarizing zone 46 and into outer and inner accumulation zones 48 aand 48 b. Since the pad 40 is stationary, a portion of the usedplanarizing solution 44 in the accumulation zones 48 a and 48 b flowsback into the areas of the planarizing zone 46 that are not occupied bythe substrate assembly 12. The characteristics of the planarizingsolution 44 in the planarizing zone 46 accordingly change throughout thefirst stage of the planarizing process because residual materials fromthe substrate 12, the pad 40, and/or the planarizing solution 44accumulate in the used planarization solution. Thus, the duration of thefirst stage of the process is generally less than the time it takes toalter the planarizing properties of the planarizing solution to a pointat which the planarizing solution does not provide consistent results.To restore the planarizing solution to a suitable state, the first stageof the planarizing cycle is terminated and the used planarizing solution44 is removed from the pad 40 by sweeping the rotating brush 184 acrossthe planarizing surface 42, as described above.

[0029] The carrier assembly 30 then commences the second stage of theplanarizing process for the substrate 12 by depositing new or additionalplanarizing solution 44 onto the planarizing surface 42 to replace theused planarizing solution that was removed by the brush 184. The carrierassembly 30 also translates the substrate 12 through the planarizingzone 46 in the presence of the fresh planarizing solution 44 until thefinal endpoint of the substrate assembly is reached. The second stage ofthe planarizing cycle is generally much shorter than the first stage,but the second stage may be approximately equal to the length of thefirst stage or even longer than the length of the first stage.Additionally, the multi-stage process for operating the planarizingmachine 10 may have more than two planarizing stages and more than onecleaning stage.

[0030] The planarizing machine 110 and the multi-stage planarizingprocess for planarizing the substrate 12 on the planarizing machine 110are particularly well suited for forming damascene interconnect lines orother metal structures on a substrate assembly. FIG. 3 is a schematiccross-sectional view of forming damascene interconnect lines on thesubstrate 12 during the first stage of the multi-stage process describedabove. In this particular embodiment, the substrate 12 has a dielectriclayer 13 with a plurality of grooves 15 that are filled by a metal coverlayer 17. The metal cover layer 17 can be composed of aluminum, copper,tungsten, titanium, titanium nitride or other suitable metals. When themetal layer 17 is composed of aluminum, the substrate assembly 12 ispreferably planarized using either a conventional CMP slurry or afixed-abrasive pad having alumina abrasive particles 45.

[0031] The first stage of the two-stage process involves translating thealuminum cover layer 17 of the substrate 12 across the planarizingsurface 42 for approximately 60-200 seconds, and preferably forapproximately 100 seconds. The planarizing solution 44 typicallyoxidizes the surface of the cover layer 17, and the alumina abrasiveparticles 45 remove the oxidized portion of the cover layer 17. Theionic form of the metal cover layer 17 accordingly enters theplanarizing solution 44. As the first stage proceeds, the usedplanarizing solution accumulates on the pad causing the concentration ofmetal ions in the solution to increase. The first stage of the process,however, is terminated before the ionic strength of the planarizingsolution reaches a threshold level at which the metal ions in theplanarizing solution can become significantly reattached to the surfaceof the substrate 12. The first stage is also terminated before the ionicstrength of the planarizing solution reaches a threshold at which thealumina abrasive particles accumulate on the pad 40 or significantlyagglomerate in the planarizing solution 44. The used planarizimgsolution 44 on the planarizing pad 40 from the first stage is thenremoved with the brush 184, as described above with respect to FIG. 2.

[0032] The second stage of the two-stage process then commences bydepositing fresh planarizing solution 44 onto the planarizing surface 42to replace the used planarizing solution 44 with a planarizing solutionhaving a lower ionic strength. The second stage of the process alsoinvolves moving the substrate 12 across the planarizing surface forapproximately 20-60 seconds, and preferably for approximately 50seconds. The second stage generally continues until the surface of thesubstrate 12 is at a final endpoint E at which the aluminum in thegrooves 15 forms damascene lines that are electrically isolated from oneanother by the dielectric layer 13.

[0033] The planarizing machine 110 and the multi-stage method ofplanarizing the substrate assembly 12 provide good results forplanarizing metal layers using stationary non-abrasive pads and abrasiveslurries, and also with fixed-abrasive pads and clean solutions. Oneaspect of the invention is the recognition that metal ions removed fromthe substrate tend to redeposit back onto the substrate when the ionicstrength of the solution increases to a threshold where theelectrostatic charge between the substrate and the slurry attracts themetal ions back to the surface of the substrate. The multi-stage processmaintains the ionic strength of the planarizing solution on theplanarizing pad below such a threshold by removing an initial batch ofused planarizing solution from the planarizing pad before the ionicstrength of the solution reaches such a threshold, and then depositing anew batch of planarizing solution at a lower ionic strength to continueplanarizing the substrate. The multi-stage process may accordingly havemore than two stages because it may be necessary to use three or morenew batches of planarizing solution on the planarizing pad to maintainthe ionic strength of the planarizing solution below such a thresholdlevel. Therefore, the planarizing machine 110 and the multi-stageprocess for operating the planarizing machine 110 is expected tosubstantially prevent redeposition or reattachment of metal ions backonto the substrate 12.

[0034] The planarizing machine 110 and the multi-stage method foroperating the planarizing machine 110 also provide good results for CMPof metal layers because the ionic strength of the slurry can bemaintained below the threshold level at which abrasive particlesagglomerate in the slurry or accumulate on the planarizing pad. Anotheraspect of the invention is the recognition that the increase in theionic strength of the planarizing solution causes the abrasive particlesin the slurry to accumulate on the pad and agglomerate in the slurry.The multi-stage process for operating the planarizing machine 110prevents the ionic strength of the planarizing solution from increasingto such a threshold. Therefore, the planarizing machine 110 and themulti-stage method for operating the planarizing machine 110 are alsoexpected to enhance the consistency of the slurry.

[0035]FIG. 4 is a schematic isometric view partially illustrating aplanarizing machine 210 with a planarizing solution removing unit 280for intermittently removing used planarizing solution 44 from the pad 40in accordance with another embodiment of the invention. In thisembodiment, the removing unit 280 has an actuator 282 attached to thegantry 34 and a vacuum assembly 284 coupled to the actuator 282. Thevacuum assembly 284 has an elongated nozzle 285 that rests upon theplanarizing surface 42. The vacuum assembly 284 can also have a vacuumsource (not shown) coupled to the nozzle 285.

[0036] In operation, the actuator 282 sweeps the nozzle 285 across theplanarizing surface 42 as the vacuum source draws a vacuum through thenozzle 285. The vacuum assembly accordingly sucks the used planarizingsolution 44 from the pad 40. The planarizing machine 210 is preferablyused between stages of a multi-stage planarizing process as describedabove. For example, the substrate 12 is planarized on the planarizingsurface 42 to an intermediate point during a first stage, and then thecarrier assembly 30 lifts the substrate assembly 12 from the planarizingsurface 42 so that the vacuum assembly 284 can sweep across theplanarizing surface and remove the used planarizing solution 44 from theplanarizing pad 40. After the vacuum assembly 284 is cleared from theplanarizing zone 46, the carrier assembly 30 reengages the substrate 12with the planarizing surface 42 and deposits fresh planarizing solutiononto the planarizing pad 40 to perform the second stage of the processin which additional material is removed from the substrate 12 to thefinal endpoint. It is expected that the advantages of the planarizingmachine 210 with the removing unit 280 are substantially the same asthose described above with respect to the planarizing machine 110 withthe removing unit 180.

[0037]FIG. 5 is a schematic isometric view partially illustrating aplanarizing machine 310, and FIG. 6 is a schematic cross-sectional viewof the planarizing machine 310, in accordance with another embodiment ofthe invention. The planarizing machine 310 has a supply roller 20, atake-up roller 23, and a carrier assembly 30 as described above. Theplanarizing machine 310 also has a planarizing pad 340 with aplanarizing surface 342 including a plurality of holes 343 in theaccumulation zone 48 a. The planarizing machine 310 also has a removingunit 380 including a plurality of holes 384 in the panel 16 coupled to acommon conduit 386. A vacuum source 387 can be coupled to the conduit386 and the holes 384 via a valve 388.

[0038] The planarizing machine 310 can be operated in a multi-stageprocess as described above, or it can be operated in a continuousprocess in which used planarizing solution in the accumulation zone 48 ais drawn through the holes 343 and 384 by the vacuum 387 to remove theused planarizing solutions 44 from the planarizing pad while thesubstrate 12 is being planarized. The rate at which the removing unit380 draws the used planarizing solution through the holes 343 ispreferably controlled to maintain the planarizing characteristics of theplanarizing solution at a desired level. For example, in the case ofmetal CMP, the carrier assembly 30 deposits fresh planarizing solution44 and the removing unit 380 removes used planarizing solution in amanner that maintains the ionic charge of the planarizing solution onthe planarizing pad 340 below the threshold at which ions significantlyredeposit onto the substrate 12, or the threshold at which abrasiveparticles significantly agglomerate in the planarizing solution oraccumulate on the planarizing pad 40.

[0039] In an alternative embodiment, the planarizing pad 340 also has aplurality of holes 345 in the inner accumulation zone 48 b, and theremoving unit 380 has a plurality of holes 385 under the inneraccumulation zone 48 b. The removing unit 380 in this embodimentaccordingly removes used planarizing solution from both the outer andinner accumulation zones 48 a and 48 b, respectively, duringplanarization of the substrate 12. In still another embodiment, theplanarizing pad 340 can be a porous planarizing pad without the holes343 and 345. In this embodiment, the vacuum draws the used planarizingfluid 44 through the pores of the planarizing pad and through the holes384 and 385 in the table 16.

[0040] The planarizing machine 310 is also expected to provide goodresults for CMP of metal layers and other materials because it cancontinuously maintain the ionic strength of the planarizing solution onthe planarizing pad below the threshold at which substrate materialssubstantially redeposit onto the substrate, or the threshold at whichabrasive particles substantially agglomerate in the planarizing solutionor substantially accumulate on the planarizing pad. Additionally, theplanarizing machine 310 may provide continuous planarization of thesubstrate 12 without interrupting the planarizing cycle tointermittently remove used planarizing solution from the pad 40.Therefore, the planarizing machine 310 is expected to enhance theplanarity of the finished substrates without increasing the time for theplanarizing cycles.

[0041]FIG. 7 is a schematic isometric view partially illustrating aplanarizing machine 410 for continuously planarizing the substrate 12 onthe planarizing pad 40 in accordance with another embodiment of theinvention. The planarizing machine 410 has a continuous removing unit480 attached to an arm 438 of the carrier assembly 30. The arm 438 isgenerally longer than the arm 38 shown in FIG. 2 such that the driveshaft 37 is attached to the mid-point of the arm 438. The removing unit480 preferably has a shaft 484 attached to the arm 438 at an endopposite from the shaft 39 carrying the substrate holder 32, and awiping element 482 extending from the shaft 484. The wiping element 482extends transverse to the outer and inner accumulation zones 48 a and 48b, and the wiping element 482 is spaced apart from the substrate 12. Inone embodiment, the wiping element 482 is a rotating brush similar tothat set forth above with respect to the planarizing machine 110. Inanother embodiment, the wiping element 482 is a vacuum assembly with anozzle similar to that described above with respect to the planarizingmachine 210. In still another embodiment, the wiping element is a wiperblade.

[0042] The planarizing machine 410 continuously removes used slurry fromthe planarizing pad 40 as the substrate 12 is being planarized. Moreparticularly, the carrier assembly 30 rotates the arm 438 to translateboth the wiping element 482 and the substrate 12 across the planarizingsurface 42 of the pad 40. The wiping element 482 continuously removesused planarized solution 44 from at least a portion of the accumulationzones 48 a and 48 b as the substrate 12 passes over newly depositedplanarizing solution 44 in the planarizing zone 46. Furthermore, bymounting the substrate holder 32 and the removing unit 480 at oppositeends of the arm 438, the substrate holder 32 and the removing unit 480do not interfere with the operation of each other. The planarizingmachine 410 accordingly provides good results for CMP of metal layersand other materials using stationary non-abrasive pads and abrasiveslurries in a manner similar to that discussed above with respect to theplanarizing machine 310.

[0043] From the foregoing it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

1. A method of planarizing a microelectronic-device substrate assembly,comprising: removing material from a substrate assembly by pressing thesubstrate assembly against a planarizing surface of a planarizing padand moving the substrate assembly across the planarizing surface; andreplacing at least a portion of a used volume of planarizing solution onthe planarizing surface with fresh planarizing solution by activelyremoving used planarizing solution from an accumulation zone on theplanarizing surface adjacent to a planarizing zone on the planarizingsurface with a removing unit other than solely the movement of the padand depositing fresh planarizing solution onto the planarizing pad. 2.The method of claim 1 wherein removing material from the substrateassembly comprises: performing a first planarizing stage of thesubstrate assembly by depositing an initial volume of planarizingsolution onto the planarizing surface and initially moving the substrateassembly across the planarizing surface, at least a portion of theinitial volume of planarizing solution becoming the used volumeplanarizing solution on the planarizing pad; stopping the firstplanarizing stage prior to replacing at least a portion of the usedplanarizing solution with the fresh planarizing solution; and performinga second planarizing stage of the substrate assembly after replacing theused planarizing solution with the fresh planarizing solution.
 3. Themethod of claim 2 wherein the substrate assembly has an aluminum coverlayer and the planarizing solution has alumina abrasive particles, andwherein: the first planarizing stage comprises planarizing the substrateassembly with the initial volume of planarizing solution forapproximately 100 seconds; and the second planarizing stage comprisesplanarizing the substrate assembly with the fresh planarizing solutionfor approximately 50 seconds.
 4. The method of claim 2 wherein thesubstrate assembly has a metal cover layer and the planarizing solutionhas abrasive particles, and wherein: the first planarizing stagecomprises planarizing the substrate assembly with the initial volume ofplanarizing solution for a first period of time; and the secondplanarizing stage comprises planarizing the substrate assembly with thefresh planarizing solution for a second period of time.
 5. The method ofclaim 4 wherein the metal cover layer comprises aluminum.
 6. The methodof claim 4 wherein the metal cover layer comprises tungsten.
 7. Themethod of claim 4 wherein the metal cover layer comprises copper.
 8. Themethod of claim 2 wherein the substrate assembly has a dielectric coverlayer and the planarizing solution has abrasive particles, and wherein:the first planarizing stage comprises planarizing the substrate assemblywith the initial volume of planarizing solution for a first period oftime; and the second planarizing stage comprises planarizing thesubstrate assembly with the fresh planarizing solution for a secondperiod of time.
 9. The method of claim 2 wherein the removing unitcomprises a vacuum assembly attached to an actuator, the vacuum assemblyincluding a nozzle and a vacuum source coupled to the nozzle, andwherein actively removing the used planarizing solution comprisessweeping the vacuum assembly across the pad to move the nozzle through aportion of an accumulation size and sucking the used planarizingsolution through the nozzle between the first and second planarizingstages.
 10. The method of claim 2 wherein the removing unit comprises arotating brush coupled to an actuator, and wherein actively removing theused planarizing solution comprises sweeping the rotating brush acrossthe planarizing surface in a direction counter to a rotational directionof the brush at the planarizing surface between the first and secondplanarizing stages.
 11. The method of claim 2 wherein the removing unitcomprises a brush coupled to an actuator, and wherein actively removingthe used planarizing solution comprises rotating the brush across theplanarizing surface in a direction that pushes the used planarizingsolution away from the accumulation zone.
 12. The method of claim 2wherein the planarizing pad has a plurality of holes in an accumulationzone extending through the planarizing pad from the planarizing surface,and the removing unit comprises a vacuum chamber operatively coupled tothe holes in the accumulation chamber, and wherein actively removing theused planarizing solution comprises sucking the used planarizingsolution through the holes in the planarizing pad by drawing a vacuum inthe vacuum chamber.
 13. The method of claim 2 wherein actively removingthe used planarizing solution comprises sweeping at least a portion ofthe used planarizing fluid from the planarizing pad between the firstand second planarizing stages.
 14. The method of claim 13 wherein awiper blade is attached to an arm, and wherein sweeping at least aportion of the used planarizing solution from the accumulation zonecomprises moving the arm to sweep the wiper blade across at least aportion of the planarizing pad between the first and second planarizingstages.
 15. The method of claim 1 wherein removing material from thesubstrate assembly and replacing at least a portion of the used volumeof planarizing solution occur contemporaneously to continuouslyplanarize the substrate assembly.
 16. The method of claim 15 wherein theplanarizing pad has a plurality of holes in an accumulation zone, theholes extending through the planarizing pad from the planarizingsurface, and the removing unit comprises a vacuum chamber operativelycoupled to the holes, and wherein actively removing the used planarizingsolution comprises sucking the used planarizing solution through theholes in the planarizing pad by drawing a vacuum in the vacuum chamberwhile the substrate is pressed against and moved across the planarizingsurface.
 17. The method of claim 15 wherein actively removing the usedplanarizing solution comprises wiping at least a portion of the usedplanarizing fluid from the planarizing pad while the substrate assemblyis pressed against and moved across the planarizing surface.
 18. Themethod of claim 17 wherein a wiper blade is attached to a substratecarrier assembly to extend across at least a portion of an accumulationzone in which the used planarizing solution accumulates, and whereinwiping at least a portion of the used planarizing solution from theaccumulation zone comprises rotating the carrier assembly to sweep thewiper blade through at least a portion of the accumulation zone inengagement with the planarizing surface.
 19. The method of claim 11wherein wiping used planarizing fluid from the pad comprises moving theused planarizing solution to a location on the pad where the usedsolution can be removed from the pad by one of a vacuum nozzle or adrain.
 20. The method of claim 15 wherein a rotating brush is attachedto a substrate carrier assembly to extend across at least a portion ofan accumulation zone on the pad, and wherein actively removing usedplanarizing solution from the pad comprises translating the carrierassembly to move the rotating brush through at least a portion of theaccumulation zone in a direction counter to a rotational direction ofthe brush at the planarizing surface.
 21. The method of claim 15 whereina vacuum assembly with an elongated nozzle is attached to a substratecarrier assembly having a substrate holder to hold the substrateassembly, the elongated nozzle extending across at least a portion of anaccumulation zone, and wherein actively removing used planarizingsolution from the pad comprises translating the carrier assembly to movethe nozzle through at least a portion of the accumulation zone andsucking used planarizing solution into the nozzle.
 22. The method ofclaim 1 wherein replacing at least a portion of a used volume ofplanarizing solution comprises performing the act of replacing afterplanarizing each substrate assembly.
 23. The method of claim 1 whereinthe act of replacing occurs without removing the polishing pad from aplanarizing station under a substrate holder.
 24. A method ofplanarizing microelectronic-device substrate assemblies, comprising:depositing fresh planarizing solution onto a planarizing surface of astationary planarizing pad; removing material from a substrate assemblyby pressing the substrate assembly against the planarizing surface,holding the planarizing pad stationary, and moving the substrateassembly across the planarizing surface; and actively removingplanarizing solution deposited on the planarizing surface from theplanarizing pad with a removing unit.
 25. The method of claim 24wherein: depositing fresh planarizing solution and removing materialfrom the substrate comprises performing a first planarizing stage bydispensing an initial volume of fresh planarizing solution onto the padand removing material from the substrate to an intermediate point, andperforming a second planarizing stage by dispensing a subsequent volumeof planarizing solution onto the pad and removing additional materialfrom the substrate to a final endpoint; and actively removingplanarizing solution from the pad is performed between the first andsecond planarizing stages to remove the initial volume of planarizingsolution used during the first planarizing stage.
 26. The method ofclaim 24 wherein depositing fresh planarizing solution onto the pad,removing material from the substrate assembly, and actively removingused planarizing solution from the pad occur contemporaneously tocontinuously planarize the substrate assembly.
 27. A method ofplanarizing a microelectronic-device substrate assembly, comprising:removing material from a substrate assembly by pressing the substrateassembly against a planarizing surface of a planarizing pad and movingthe substrate assembly across the planarizing surface; and exchanging atleast a portion of a used volume of planarizing solution on theplanarizing pad with fresh planarizing solution by actively removingused planarizing solution from an accumulation zone on the planarizingpad adjacent to a planarizing zone with an active removing unit otherthan solely the movement of the pad and depositing fresh planarizingsolution in the planarizing zone.
 28. The method of claim 27 whereinremoving material from the substrate assembly comprises: performing afirst planarizing stage of the substrate assembly by depositing aninitial volume of planarizing solution onto the planarizing surface andinitially moving the substrate assembly across the planarizing surface,at least a portion of the initial volume of planarizing solutionbecoming the used volume planarizing solution on the planarizing pad;stopping the first planarizing stage prior to exchanging at least aportion of the used planarizing solution with the fresh planarizingsolution; and performing a second planarizing stage of the substrateassembly after exchanging the used planarizing solution with the freshplanarizing solution.
 29. The method of claim 28 wherein the substrateassembly has an aluminum cover layer and the planarizing solution hasalumina abrasive particles, and wherein: the first planarizing stagecomprises planarizing the substrate assembly with the initial volume ofplanarizing solution for approximately 100 seconds; and the secondplanarizing stage comprises planarizing the substrate assembly with thefresh planarizing solution for approximately 50 seconds.
 30. The methodof claim 28 wherein the removing unit comprises a vacuum assemblyattached to an actuator, the vacuum assembly including a nozzle and avacuum source coupled to the nozzle, and wherein actively removing theused planarizing solution comprises sweeping the vacuum assembly acrossthe pad to move the nozzle through at least a portion of theaccumulation zone and sucking the used planarizing solution through thenozzle between the first and second planarizing stages.
 31. The methodof claim 28 wherein the removing unit comprises a rotating brush coupledto an actuator, and wherein actively removing the used planarizingsolution comprises sweeping the rotating brush across the planarizingsurface in a direction counter to a rotational direction of the brush atthe planarizing surface between the first and second planarizing stages.32. The method of claim 27 wherein removing material from the substrateassembly and exchanging at least a portion of the used volume ofplanarizing solution occur contemporaneously to continuously planarizethe substrate assembly.
 33. The method of claim 32 wherein theplanarizing pad has a plurality of holes in the accumulation zone, theholes extending through the planarizing pad from the planarizingsurface, and the removing unit comprises a vacuum chamber operativelycoupled to the holes, and wherein actively removing the used planarizingsolution comprises sucking the used planarizing solution through theholes in the planarizing pad by drawing a vacuum in the vacuum chamberwhile the substrate is pressed against and moved across the planarizingsurface.
 34. The method of claim 32 wherein a rotating brush is attachedto a substrate carrier assembly to extend across at least a portion ofthe accumulation zone on the pad, and wherein actively removing usedplanarizing solution from the pad comprises rotating the carrierassembly to move the rotating brush through at least a portion of theaccumulation zone in a direction counter to a rotational direction ofthe brush at the planarizing surface.
 35. The method of claim 32 whereina vacuum assembly with an elongated nozzle is attached to a substratecarrier assembly having a substrate holder to hold the substrateassembly, the elongated nozzle extending across at least a portion ofthe accumulation zone, and wherein actively removing used planarizingsolution from the pad comprises rotating the carrier assembly to movethe nozzle through at least a portion of the accumulation zone andsucking used planarizing solution into the nozzle.
 36. A method ofplanarizing a microelectronic-device substrate assembly, comprising:removing material from a substrate assembly by pressing the substrateassembly against a planarizing surface of a planarizing pad and movingthe substrate assembly across the planarizing surface; and maintainingan ionic charge level of the planarizing solution below a thresholdlevel by exchanging used planarizing solution deposited onto theplanarizing pad with fresh planarizing solution using means other thansolely the movement of the pad, the threshold level being one of chargelevel at which ionic material removed from the substrate assemblysubstantially reattaches to the substrate assembly, or a charge level atwhich abrasive particles in the slurry substantially agglomerate in theslurry or substantially accumulate on the planarizing surface.
 37. Themethod of claim 36 wherein removing material from the substrate assemblycomprises: performing a first planarizing stage of the substrateassembly by depositing an initial volume of planarizing solution ontothe planarizing surface and initially moving the substrate assemblyacross the planarizing surface, at least a portion of the initial volumeof planarizing solution becoming the used volume planarizing solution onthe planarizing pad; stopping the first planarizing stage prior toexchanging at least a portion of the used planarizing solution with thefresh planarizing solution; and performing a second planarizing stage ofthe substrate assembly after exchanging the used planarizing solutionwith the fresh planarizing solution.
 38. The method of claim 37 whereinthe substrate assembly has an aluminum cover layer and the planarizingsolution has alumina abrasive particles, and wherein: the firstplanarizing stage comprises planarizing the substrate assembly with theinitial volume of planarizing solution for approximately 100 seconds;and the second planarizing stage comprises planarizing the substrateassembly with the fresh planarizing solution for approximately 50seconds.
 39. The method of claim 37 wherein the removing unit comprisesa vacuum assembly attached to an actuator, the vacuum assembly includinga nozzle and a vacuum source coupled to the nozzle, and wherein activelyremoving the used planarizing solution comprises sweeping the vacuumassembly across the pad to move the nozzle through at least a portion ofthe accumulation zone and sucking the used planarizing solution throughthe nozzle between the first and second planarizing stages.
 40. Themethod of claim 37 wherein the removing unit comprises a rotating brushcoupled to an actuator, and wherein actively removing the usedplanarizing solution comprises sweeping the rotating brush across theplanarizing surface in a direction counter to a rotational direction ofthe brush at the planarizing surface between the first and secondplanarizing stages.
 41. The method of claim 36 wherein removing materialfrom the substrate assembly and exchanging at least a portion of theused volume of planarizing solution occur contemporaneously tocontinuously planarize the substrate assembly.
 42. The method of claim41 wherein the planarizimg pad has a plurality of holes in anaccumulation zone, the holes extending through the planarizing pad fromthe planarizing surface, and the removing unit comprises a vacuumchamber operatively coupled to the holes, and wherein actively removingthe used planarizing solution comprises sucking the used planarizingsolution through the holes in the planarizing pad by drawing a vacuum inthe vacuum chamber while the substrate is pressed against and movedacross the planarizing surface.
 43. The method of claim 41 wherein arotating brush is attached to a substrate carrier assembly to extendacross at least a portion of an accumulation zone on the pad, andwherein actively removing used planarizing solution from the padcomprises rotating the carrier assembly to move the rotating brushthrough at least a portion of the accumulation zone in a directioncounter to a rotational direction of the brush at the planarizingsurface.
 44. The method of claim 41 wherein a vacuum assembly with anelongated nozzle is attached to a substrate carrier assembly having asubstrate holder to hold the substrate assembly, the elongated nozzleextending across at least a portion of an accumulation zone, and whereinactively removing used planarizing solution from the pad comprisesrotating the carrier assembly to move the nozzle through at least aportion of the accumulation zone and sucking used planarizing solutioninto the nozzle.
 45. A method of planarizing a microelectronic-devicesubstrate assembly, comprising: removing material from a substrateassembly by pressing the substrate assembly against a planarizingsurface of a planarizing pad and moving the substrate assembly acrossthe planarizing surface; and maintaining an a pH level of theplanarizing solution below a threshold level by exchanging usedplanarizing solution deposited onto the planarizing pad with freshplanarizing solution using means other than solely the movement of thepad, the threshold level being a pH level that adversely affects thesubstrate assembly.
 46. A method of planarizing a microelectronic-devicesubstrate assembly, comprising: removing material from a substrateassembly by pressing the substrate assembly against a planarizingsurface of a planarizing pad and moving the substrate assembly acrossthe planarizing surface; and maintaining a percent solids level of theplanarizing solution below a threshold level by exchanging usedplanarizing solution deposited onto the planarizing pad with freshplanarizing solution using means other than solely the movement of thepad, the threshold level being one of a solids level at which materialremoved from the substrate assembly substantially reattaches to thesubstrate assembly, or a solids level at which abrasive particles in theslurry substantially agglomerate in the slurry or substantiallyaccumulate on the planarizing surface.
 47. The method of claim 46wherein maintaining a percent solids comprises keeping not more than 1%solids in the planarizing solution on the pad.
 48. The method of claim46 wherein maintaining a percent solids comprises keeping not more than0.1% solids in the planarization solution on the pad.
 49. A planarizingmachine for planarizing microelectronic-device substrate assemblies,comprising: a table with a support panel; a planarizing pad including aplanarizing surface facing away from the support panel, the planarizingpad being removably attached to the support panel; a carrier assemblyhaving a substrate holder positionable over the planarizing pad and aplanarizing solution dispenser to dispense a fresh planarizing solutiononto the planarizing surface, the substrate holder translating asubstrate assembly over a planarizing zone of the planarizing surfaceduring a planarizing cycle, and the substrate assembly pushing usedplanarizing solution deposited onto the planarizing pad into anaccumulation zone on the planarizing surface adjacent to the planarizingzone; and a planarizing solution removing unit at the accumulation zone,the removing unit actively removing used planarizing solution from atleast a portion of the accumulation zone on the stationary planarizingpad.
 50. The planarizing machine of claim 49 wherein the removing unitcomprises a vacuum assembly having a nozzle positionable in theaccumulation zone to be exposed to at least a portion of the usedplanarizing solution and a vacuum source coupled to the nozzle to suckthe used planarizing solution through the nozzle.
 51. The planarizingmachine of claim 49 wherein: the planarizing pad has a plurality ofholes in the accumulation zone extending through the planarizing padfrom the planarizing surface; and the removing unit comprises a vacuumchamber operatively coupled to the holes in the planarizing pad and avacuum source coupled to the vacuum chamber, the vacuum source suckingthe used planarizing solution through the holes in the planarizing padand the vacuum chamber.
 52. The planarizing machine of claim 49 whereinthe removing unit comprises a pipette having a pipe, a cylinder attachedto the pipe and plunger coupled to the cylinder to draw a volume offluid through the pipe and into the cylinder.
 53. The planarizingmachine of claim 49, further comprising a wiper blade attached to thecarrier assembly to extend across at least a portion of the accumulationzone, the wiper blade being spaced apart from the substrate holder. 54.The planarizing machine of claim 49, further comprising a wiper bladeattached to an arm separate from the carrier assembly, the arm beingmovable over the accumulation zone to sweep the wiper blade across atleast a portion of the accumulation zone.
 55. The planarizing machine ofclaim 49, further comprising a rotating brush attached to the carrierassembly, the rotating brush being spaced apart from the substrateholder and the rotating brush extending across at least a portion of theaccumulation zone, the carrier assembly moving the rotating brushthrough at least a portion of the accumulation zone apart from thesubstrate assembly.
 56. The planarizing machine of claim 49, furthercomprising a rotating brush attached to an actuator separate from thecarrier assembly, the actuator sweeping the brush over at least aportion of the accumulation zone.
 57. The planarizing machine of claim49, further comprising a vacuum assembly attached to the carrierassembly, the vacuum assembly having a nozzle spaced apart from thesubstrate holder and the nozzle extending across at least a portion ofthe accumulation zone, the carrier assembly moving the nozzle through atleast a portion of the accumulation zone apart from the substrateassembly.
 58. The planarizing machine of claim 49, further comprising avacuum assembly attached to an actuator separate from the carrierassembly, the vacuum assembly having a nozzle adapted to engage theplanarizing surface of the pad, and the actuator sweeping the nozzleover at least a portion of the accumulation zone.
 59. A planarizingmachine for planarizing microelectronic-device substrate assemblies,comprising: a table with a support panel; a supply roller proximate tothe support panel; a take-up roller proximate to the support panel; aweb-format planarizing pad including a pre-operative portion wrappedaround the supply roller, an operative portion removably attached to thesupport panel to remain stationary during a planarizing cycle, and apost-operative portion wrapped around the take-up roller, theplanarizing pad having a planarizing surface exposed in the operativeportion facing away from the support panel; a carrier assembly having asubstrate holder positionable over the planarizing pad and a planarizingsolution dispenser to dispense a fresh planarizing solution onto theplanarizing surface, the substrate holder translating a substrateassembly over a planarizing zone of the planarizing surface during theplanarizing cycle, and the substrate assembly pushing used planarizingsolution deposited onto the planarizing pad into an accumulation zone onthe planarizing surface adjacent to the planarizing zone; and aplanarizing solution removing unit other than the substrate assemblypositioned proximate to the accumulation zone on the planarizingsurface.
 60. The planarizing machine of claim 59 wherein the removingunit comprises a vacuum assembly having a nozzle positionable in theaccumulation zone to be exposed to at least a portion of the usedplanarizing solution and a vacuum source coupled to the nozzle to suckthe used planarizing solution through the nozzle.
 61. The planarizingmachine of claim 59 wherein: the planarizing pad has a plurality ofholes in the accumulation zone extending through the planarizing padfrom the planarizing surface; and the removing unit comprises a vacuumchamber operatively coupled to the holes in the planarizing pad and avacuum source coupled to the vacuum chamber, the vacuum source suckingthe used planarizing solution through the holes in the planarizing padand the vacuum chamber.
 62. The planarizing machine of claim 59, furthercomprising a rotating brush attached to the carrier assembly, therotating brush being spaced apart from the substrate holder and therotating brush extending across at least a portion of the accumulationzone, the carrier assembly moving the rotating brush through at least aportion of the accumulation zone apart from the substrate assembly. 63.The planarizing machine of claim 59, further comprising a rotating brushattached to an actuator separate from the carrier assembly, the actuatorsweeping the brush over at least a portion of the accumulation zonebetween planarizing stages of a multi-stage planarizing cycle.
 64. Theplanarizing machine of claim 59, further comprising a vacuum assemblyattached to the carrier assembly, the vacuum assembly having a nozzlespaced apart from the substrate holder and the nozzle extending acrossat least a portion of the accumulation zone, the carrier assembly movingthe nozzle through at least a portion of the accumulation zone apartfrom the substrate assembly.
 65. The planarizing machine of claim 59,further comprising a vacuum assembly attached to an actuator separatefrom the carrier assembly, the vacuum assembly having a nozzle adaptedto engage the planarizing surface of the pad, and the actuator sweepingthe nozzle over at least a portion of the accumulation zone betweenplanarizing stages of a multi-stage planarizing cycle.
 66. A planarizingmachine for planarizing microelectronic-device substrate assemblies,comprising: a table with a stationary support panel; a supply rollerproximate to the support panel; a take-up roller proximate to thesupport panel; a web-format planarizing pad including a pre-operativeportion wrapped around the supply roller, an operative portion removablyattached to the support panel to remain stationary during a planarizingcycle, and a post-operative portion wrapped around the take-up roller,the planarizing pad having a planarizing surface exposed in theoperative portion facing away from the support panel; a carrier assemblyhaving a substrate holder positionable over the planarizing pad and aplanarizing solution dispenser to dispense a fresh planarizing solutiononto the planarizing surface, the substrate holder translating asubstrate assembly over a planarizing zone of the planarizing surfaceduring the planarizing cycle, and the substrate assembly pushing usedplanarizing solution deposited onto the planarizing pad into anaccumulation zone on the planarizing surface adjacent to the planarizingzone; and a planarizing solution removing unit at the accumulation zoneto remove at least a portion of the planarizing solution deposited ontothe planarizing surface while the planarizing pad remains stationary.67. The planarizing machine of claim 66 wherein the removing unitcomprises a vacuum assembly having a nozzle positionable in theaccumulation zone to be exposed to at least a portion of the usedplanarizing solution and a vacuum source coupled to the nozzle to suckthe used planarizing solution through the nozzle.
 68. The planarizingmachine of claim 66 wherein: the planarizing pad has a plurality ofholes in the accumulation zone extending through the planarizing padfrom the planarizing surface; and the removing unit comprises a vacuumchamber operatively coupled to the holes in the planarizing pad and avacuum source coupled to the vacuum chamber, the vacuum source suckingthe used planarizing solution through the holes in the planarizing padand the vacuum chamber.
 69. The planarizing machine of claim 66, furthercomprising a rotating brush attached to the carrier assembly, therotating brush being spaced apart from the substrate holder and therotating brush extending across at least a portion of the accumulationzone, the carrier assembly moving the rotating brush through at least aportion of the accumulation zone apart from the substrate assembly. 70.The planarizing machine of claim 66, further comprising a rotating brushattached to an actuator separate from the carrier assembly, the actuatorsweeping the brush over at least a portion of the accumulation zonebetween planarizing stages of a multi-stage planarizing cycle.
 71. Theplanarizing machine of claim 66, further comprising a vacuum assemblyattached to the carrier assembly, the vacuum assembly having a nozzlespaced apart from the substrate holder and the nozzle extending acrossat least a portion of the accumulation zone, the carrier assembly movingthe nozzle through at least a portion of the accumulation zone apartfrom the substrate assembly.
 72. The planarizing machine of claim 66,further comprising a vacuum assembly attached to an actuator separatefrom the carrier assembly, the vacuum assembly having a nozzle adaptedto engage the planarizing surface of the pad, and the actuator sweepingthe nozzle over at least a portion of the accumulation zone betweenplanarizing stages of a multi-stage planarizing cycle.